High speed oil circuit breaker



Patented Aug. 25, 1931 UNFTE) STATES PATENT OFFICE REINHOLD RUDENBERG, OF BERLIN-GRUNEWALD, GERMANY, SSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, .A CORPORATION OF PENNSYL- VANIA HIGH SPEED OIL CIRCUIT BREAKER Application filed April 9, 1.927, Serial No.

My invention relates to circuit interrupters and particularly to the high-speed contact members therefor.

One object of my invention is to provide a circuit interrupter with main and auxil lary contact members that shall open a eircuit at high speed.

Another object of my invention is to provide the main and auxiliary Contact members of a circuit interrupter with independent supporting and actuating mechanisms.

A farther object of my invention is to provide a common operating member tor transmitting motion to the independent actuating mechanisms that operate the contact members.

In any circuit-opening device having main and auxiliary contact members, the main contact members are arranged to completely open before the auxiliary or arcingl contact members are separated. rlhis sequence of ope ation eliminates arcing from the main contact members on opening, so that good contact surface therebetween in the closed 'position is guaranteed.

l-lereto'fore, the arcing and main Contact members of an oil-immersed circuit interrupter have been supported on a single lift rod and resiliently connected to each other in such manner that the main Contact members open first and are followed by the arcing contact members. This required a very heavy member for the main moving contacts with the additional hinged or otherwise ilexibie supports for the auxiliary Contact members together with the necessary biasing elements to assist in the speed of opening of the d auxiliary contact members. The inertia of the heavy moving Contact members, with the resistance offered by the biasing means, opposes the initial opening movement of the contact members and retards their speed of separation.

ln order to obtain a high rate oiE opening speed, the moving masses mnst be as small 182,292, and in Germany April 23, 1926.

as possible. It is for this reason that my invention employs separate lift-rods for the cont ct members, whereby the cont-act member. themselves constitute the greatest mass oil' material to be moved. rlhis is especially 'true of the main Contact members which must be of relatively larOe area in order to reduce the temperature rise therein. If a linkage mechanism is provided, in accordance with the present invention, between the main and the arcing Contact members, it is necessary to use only relatively small accelerating and retarding forces for the heavy main contact members, and the relatively light arcing Contact members may be moved much faster than would otherwise be the case.

In practicing my invention, different lever systems, connected to a common actuating means, are employed for the two sets of contact members. Relative rate of speed and sequence oi movement in the two sets of conact members is obtained by the predetermined selection of the fulcrum points and the reiative length of the connecting links and levers of the lever systems.

ln the accompanying drawings,

Figure l is a view of a circuit interrupter showing the main and auxiliary contact members and operating levers with the tank and cover in sections.

Fig. 2 is a schematic view of an arrangement of the operating levers in prospective, and

Fig. 3 is a time curve comparing the relative speed and time oi opening of the main and auxiliary contact members.

Referring to Figures l and 2 of the drawings, my invention comprises, in general, a tank l having a cover Q, thereon, main contz ct bushings 3 and 4 mounted in the cover 2 and having their ends disposed within the tank l and termin ating in the stationary main contact members 5 and G. The supporting members 7 and 8 'for the stationary auxiliary contact members 9 and 11 are electrically connected in parallel circuit with the bushings 3 and 4.

The stationary main contact members 5 and 6 are bridged by the main contact member 12, that is supported by its lift-rod 13. T he stationary auxiliary contact members 9 and 11 are bridged by the auxiliary contact member 14 that is likewise supported by its litt-rod 15. rilhe main contact member 12 is of much greater bulk than auxiliary contact member 14, as the load is carried continuously by the former when the circuit iiiterrupter is in operation. The auxiliary contact member 14 is much lighter and is utilized to rup; ture the circuit and arc incident to the opening of the circuit interrupter after the main contact member 12 is completely opened, thereby protecting it from damage due to arciiig.

The lift-rod 13 for the main contact me1n bei' 12 is pivotally supported on one end oic a link 16 that is hingedly supported at its other end to a link 17 that is ilexibly suspended from a ulcrum 18. A bell-crank 19 is piv` otally supported at a fulcrum 21 andhas one arm pivotally disposed near the mid-point of link 16. The other arm of the bell-crank 19 is hingedly attached to. the end of a link 22 at the point 23. The other end of' the link 22 is attached to the end Otan arm 24 at point 25, the arm 24 being .rigidly supported b-y a shaft 26 atthe point 27. The points23, 25 and 27 are in line, as shown on the drawings, thereby constituting a holding toggle to retain the main contact member in the operating or closed position.

The lift-rod 15 for the auxiliary or arcing contact member 14 is supported by a similar mechanical arrangement in which the liftrod 15 is hingedly attached to a link 28 that has its other end pivotally supported by a flexible suspension link 29 that, in turn, has its other end pivotally disposed on the ful crum 31.

Bell-crank 32 is pivoted on a supporting Ytiilcrun'i 33 and has one arm pivotally disposed on a link 28 in proximity to its inidseetion. Another arm of the bell-crank'33 is hingedly connected to a link 34 at a point 35. rllhe other end of the link 34 is pivotally attached to an arm 36 at a point 37. rThe arm 3G is rigidly supported on the shaft 26 at a point 38. The points 37 and 38, being in line in the closed position of the circuit interrupter, constitute a toggle for retaining the secondary arcing Contact .14 in the operating position of the circuit interrupter.

Assuming the circuit interrupter 1 to be in the closed position shown in Fig. 1, the contact members 12 and 14 are held in their closed positions by the toggles constituted by the link 22 and the arm 24 and by link 34 and arm 36 having the points 23, 25 and 27 in the former and the points 35, 37 and 38 of the latter in a direct line.

Upon a counter-clockwise movement of the shai't 26, the points and 37 oi the arms 24 and moved out of line with the points 23, 25 and 35, 38, respectively, and the contact members 12 and 14 are released. A further turning` movement of the shaft 26 operates the links 22 and 34, the bell-cranks 19 and and the links 16 and 28 Wh'ch, in turn, completely opens the contact members 12 and 14 by the movement of the litt-rods 13 and 15.

By a predetermined choice of the lengths of the arms 24 and 36, the bell-crank 19 and 32, the links 22, 34, 16 and 28, and ot the positions ot' the iulcrums 18, 21, 31 and 33, the relative speed and sequence of operation of the Contact members 12 and 14 may be predicted. The arrangement, chosen 'lor the Figures 1 and 2 ot the-attached drawings, is graphicallyv shown in Fig. 3 in Which S is the distance passed over, and V1 and V2 the speed of opening of the main and auxiliary contact members, respectively. It will be seen that the main contact member 12 has an opening speed V1 that increases quickly t-o a maximum value While the opening speed V2 of the auxiliary contact member 14 remains small as long as the ma in contact meniber 12 is being accelerated. During this time, the initial movement of the auxiliary contact member 14 is small and will not be sullicient to permit its separation from the stationary auxiliary contact members 9 and 11 until after the main contact member 12 has completely parted from the main stationary contact n'iembers 5 and 6. After the separation ot the main contact member 12, the auxiliary contact member 14 becomes accelerated, as represented by curve V2 in Fig. 3 ci drawings, to quickly separate from the auxiliary contact member 9 and 11, thereby interrupting the circuit, in circuit interruptn er 1, at high speed Without damage to the stationary or moving contact members 5, 6 and 11.

Accordingly, my invention overcomes thc diii'iculty experienced in circuit interruptcrs that have the speed ot opening of' the contact members retarded because of the inertia of the masses of the contact men'ibcrs and the operating mechanism. By the use of individual lift rods, the contact members that I employ are made of' lighter material, the heaviest part of which will be the main contact member, the size of which is limited to a suliicient cross-sectional area to prevent its heating While in operation. By iising separate systems of transmission levers to operate the diiterent lift rods and by ykeeping the moving masses ot the circuit interrupter as small as possible, I am ablel to obtain any sequence or relative speed in the operation of the main and auxiliary contact members. By choosing the lengths oi the links and bell-crank arms, as in Figures 1 and 2 of the attached drawings, I am able to obtain quick opening of the main contact member and a high speed of operation of the auxiliary Contact member, resulting in the interruption of the circuit at high speed without damage to the main stationary contact member or to the main moving contact member.

It is to be understood that such changes in the formal arrangement and connection of the component parts of my invention may be made as shall fall within the scope of the appended claims.

I claim as my invention:

1. In a circuit interrupter, the combination with separate supporting means for main and arcing contact members, independent leverage means for connecting the supporting means to a common transmission mechanism, whereby the operation of the main and arcing contact members occurs in a predetermined sequence of movement and speed by means independent of each other.

2. In a circuit interrupter, the combination with separate supporting means for main and arciimr contact members, a plurality of lever systems for independently connecting the supporting means to a common transmission mechanism, whereby the operation of the main and arcing contact members occurs in a predetermined sequence of movement and speed by lever systems that are independent of each other.

3. In a circuit interrupter, the combination with separate supporting means for main and arcing Contact members, a plurality of linkage systems comprising separate mechanical elements for independently connecting the supporting means to a common transmission mechanism, whereby the operation of the main and arcing Contact members is accomplished by the linkage systems that are independent of each other.

4. In a circuit interrupter, the combination with main and arcing contact members and independent lift rods for their support, a plurality of systems of mechanical elements joining the independent lift rods to a common operating means, whereby the main and arcing contact members are operated independently and relatively to each other by the common operating means.

5. In a circuit interrupter, the combination with main and areing contact members and independent lift rods for their support, mechanical elements forming distinct lever systems connected to each of the lift rods, an energy-transmission mechanism common t0 the lever systems, whereby, upon the actuation of the energy transmission mechanism, relative movements in sequence and speed are imparted to the main and arcing contact members.

REINHOLD RUDENBERG. 

